Add a new async awaiter for returning to a named thread from somewher…

…e else

Plugins/UE5Coro/Source/UE5Coro/Private/AsyncAwaiters.cpp

@@ -84,6 +84,11 @@ FAsyncAwaiter Async::MoveToGameThread()
 	return FAsyncAwaiter(ENamedThreads::GameThread);
 }
 
+FAsyncAwaiter Async::MoveToSimilarThread()
+{
+	return FAsyncAwaiter(FTaskGraphInterface::Get().GetCurrentThreadIfKnown());
+}
+
 FAsyncYieldAwaiter Async::Yield()
 {
 	return {};

Plugins/UE5Coro/Source/UE5Coro/Public/UE5Coro/AsyncAwaiters.h

@@ -65,6 +65,12 @@ UE5CORO_API Private::FAsyncAwaiter MoveToThread(ENamedThreads::Type);
  *  the game thread. */
 UE5CORO_API Private::FAsyncAwaiter MoveToGameThread();
 
+/** Convenience function to resume on the same kind of named thread that this
+ *  function was called on.<br>
+ *  co_await MoveToSimilarThread() is not useful. The return value should be
+ *  stored to "remember" the original thread, then co_awaited later. */
+UE5CORO_API Private::FAsyncAwaiter MoveToSimilarThread();
+
 /** Always suspends the coroutine and resumes it on the same kind of named
  *  thread that it's currently running on, or AnyThread otherwise.<br>
  *  The return value of this function is reusable and always refers to the

Plugins/UE5Coro/Source/UE5CoroTests/Private/AsyncAwaiterTest.cpp

@@ -139,6 +139,24 @@ void DoTest(FAutomationTestBase& Test)
 		Test.TestTrue(TEXT("Triggered"), CoroToTest->Wait());
 	}
 
+	{
+		FEventRef CoroToTest;
+		std::atomic<bool> bMovedOut = false;
+		std::atomic<bool> bMovedIn = false;
+		World.Run(CORO
+		{
+			auto Return = Async::MoveToSimilarThread();
+			co_await Async::MoveToNewThread();
+			bMovedOut = !IsInGameThread();
+			co_await Return;
+			bMovedIn = IsInGameThread();
+			CoroToTest->Trigger();
+		});
+		FTestHelper::PumpGameThread(World, [&] { return CoroToTest->Wait(0); });
+		Test.TestTrue(TEXT("Moved out"), bMovedOut);
+		Test.TestTrue(TEXT("Moved back in"), bMovedIn);
+	}
+
 	{
 		std::atomic<int> State = 0;
 		World.Run(CORO